Switchover Valve Cleaned! Presto!! - PeachParts Mercedes-Benz Forum

tobybul · #1 04-03-2007, 06:21 PM

Today, I read Steve Brotherton's article on Transmission Fine Tuning from the DIY Articles above. In the later part, he talked about how the banjo and the switchover valve get dirty. I have been into the banjo's at least twice in the past but not on the switchover valve.

I don't know why I didn't look into this sooner but I finally removed and cleaned the switchover valve of the 85D and to my amazement, picked up some power

.

Sorry I did not think about taking pics

but all I did was unfastened the valve from the fire wall and unhooked the 2 boost lines and the electrical plug. Got some brake cleaner spray and sprayed the inside of the boost connections. It seemed more effective spraying thru the bottom connection as it pushed the gunk out thru the side connection (not sure what the top connection with the cap is for).

There was black stuff (soot) that came out just like Steve said. I sprayed it till the cleaner came out clear. I used brake cleaner b/c it dries quick. Also had the jet straw attached to the spray

Thoroughly dried valve with some compressed air and put it back. I also readjusted the ALDA back to its original position (I had it 1/2 turn CCW). Test drove the car and I swear, it was as if the ALDA was turned up.

Don't know if this will work for anyone else but I had this sluggish pickup since I got the car last year. Dirty switchover valve appears to have been the cause.

300SD81 · #2 04-03-2007, 06:29 PM

The top connection with the cap is a vent thats connected to the alda when theres overboost. Its useful when those valves are used as vacuum switches..

Motorhead · #3 04-03-2007, 08:20 PM

Un-hook the EGR valve if it has not already been done. It contributes to the GUNK in the intake manafold plus, It will run even better.

tobybul · #4 04-04-2007, 08:33 AM

Quote:

Originally Posted by Motorhead

Un-hook the EGR valve if it has not already been done. It contributes to the GUNK in the intake manafold plus, It will run even better.

Thanks. I've thought about that. Its been suggested a few times in the forum. I may have to give in someday. Kinda wanted to keep things original...

WINGAS · #5 04-04-2007, 09:50 AM

I'm jealous of yous guys with hair dryers under the hood...

Matt L · #6 04-04-2007, 10:02 AM

Quote:

Originally Posted by 427L88

I'm jealous of yous guys with hair dryers under the hood...

I'm not. Our NA 606's put out more power than their blown engines. Of course, that doesn't mean that I would turn down a nice turbo CDI.

Motorhead · #7 04-04-2007, 04:37 PM

Quote:

Originally Posted by tobybul

Thanks. I've thought about that. Its been suggested a few times in the forum. I may have to give in someday. Kinda wanted to keep things original...

All you have to do is put a small BB in the vacuum line that hooks to the EGR valve. Put the BB in the short black rubber hose between the EGR valve and the plastic hard line. ONLY you will know!!! Believe me.... You will be glad you plugged it off.

crashone · #8 04-04-2007, 07:52 PM

Question-- I pulled an extra switch over valve from the boneyard and I see now that the top cap is missing. Will it still work right or what? Thanks.

pawoSD · #9 04-04-2007, 09:01 PM

Quote:

Originally Posted by tobybul

Today, I read Steve Brotherton's article on Transmission Fine Tuning from the DIY Articles above. In the later part, he talked about how the banjo and the switchover valve get dirty. I have been into the banjo's at least twice in the past but not on the switchover valve.

I don't know why I didn't look into this sooner but I finally removed and cleaned the switchover valve of the 85D and to my amazement, picked up some power

.

Sorry I did not think about taking pics

but all I did was unfastened the valve from the fire wall and unhooked the 2 boost lines and the electrical plug. Got some brake cleaner spray and sprayed the inside of the boost connections. It seemed more effective spraying thru the bottom connection as it pushed the gunk out thru the side connection (not sure what the top connection with the cap is for).

There was black stuff (soot) that came out just like Steve said. I sprayed it till the cleaner came out clear. I used brake cleaner b/c it dries quick. Also had the jet straw attached to the spray

Thoroughly dried valve with some compressed air and put it back. I also readjusted the ALDA back to its original position (I had it 1/2 turn CCW). Test drove the car and I swear, it was as if the ALDA was turned up.

Don't know if this will work for anyone else but I had this sluggish pickup since I got the car last year. Dirty switchover valve appears to have been the cause.

Very cool, I never thought to do that, I think I will clean out my boost line and switchover valve sometime soon...to see if it improves anything.

tobybul · #10 04-04-2007, 10:35 PM

Quote:

Originally Posted by pawoSD

Very cool, I never thought to do that, I think I will clean out my boost line and switchover valve sometime soon...to see if it improves anything.

PawoSD, when I drove to work today, around town and back home, I was quite delighted.... the cleaning of the switchover valve is what the D was looking for. I guess it probably puts it back to how it was originally intended to run. I could even distinctly feel the turbo kicking in whenever I hit the pedal.

No doctoring of any other part such as ALDA adjustment nor wastegate tweeking was necessary.

The gunk in the valve must have restricted the boost to the ALDA. In a way, it made sense for the valve to get plugged up after 20+ years. Heck, this thing has probably been this way for years.

The normal diameter of the passage thru the valve is less than half of the boost line's diameter. So, its a constriction that attracts and accumulates soot which eventually plugs it up.

crashone · #11 04-10-2007, 09:27 PM

All right check this out. Since no one could answer my question I did some experimenting. I took both switches and cleaned them out really well. I installed the one without the cap and noticed a big improvement. I went back to the one with a cap and noticed that it lacked the same pep, more sluggish. Went back to the one without the cap and left it alone. The response is unbelievable. It seems like I don't have to keep my foot in it as hard to get going. The next time you are in the boneyards pull one and remove the cap, clean it out and try it. I am not sure what is being done by doing this but it sure is nice having some get up and go.

300SD81 · #12 04-10-2007, 09:35 PM

I doubt the cap had anything to do with it. Try pulling the cap off your old one and putting it on your new one... The old one probably leaked.

pawoSD · #13 04-11-2007, 12:54 AM

I went out and did this about an hour ago....I took the valve off, sprayed brake cleaner through it on both sides, and some soot came out with the spray...sprayed some into the boost lines leading to the alda and the intake....put it back together and......crank...slowcrankPOOM, silence. (The POOM made me let go of the key

) So I thought, oh great, I just blew up my engine with brake cleaner fumes. So I tried to start it again, and it cranked over fine but made some sputtering/popping sounds and was unhappy for about 3-5 seconds, made some smoke in the exhaust, then got going ok. I let it warm up idling...sounded fine....and took it for an extended test drive (23 miles

) Power is UP! I could notice it right away, more boost response at lower speeds now. I went on the freeway for about 7-8 miles at 75mph....and it was fine, and power is up there too...it goes from 65 to 85 in no time!!

Moral of story, clean out valve and lines, do not spray brake cleaner into intake, it makes a 617 upset.

rbardolv · #14 05-06-2007, 05:04 PM

I can't seem to find that switch over valve anywhere. I cleaned out the banjo at the manifold and the lines, (they were dirty). Cleaned the lines from the "thingY' at the IP with the vac lines all going to it and other banjo ,(Could this be the alda?), with the green filter looking thing next to it. ANyhow thats all the vac lines I could trace... There is one in by the firewall but that goes into the cab and thats it.. No switch with vac lines mounted on the firewall. I have an 83' 300SD california emissions , says the window sticker....

Any help is appreciated. I guess I may not have that firewall mounted switch? (possible?)

ALso, is the ERG valve that metal looking thing in front of the engine closer to the turbine area with a brown vac line going into the top of it?

Cheers!

toomany MBZ · #15 05-06-2007, 05:23 PM

The switchover valve on an SD is located on the firewall closest to front about 8 inches away from IP, which has the ALDA on top. You'll see a number of lines going to it, including a clear line from turbo, on bottom, another clear line from ALDA on top. And an electrical plug. Mine, anyway.